1. Field of the Invention
The present invention relates to an EL panel.
2. Related Background Art
EL (Electro Luminescence) elements such as organic EL and inorganic EL are included in a selfluminous type light-emitting element, which has a characteristic that it is easy to make it smaller and lighter, as well as a high brightness, and therefore the EL elements are expected to be applied to displays, illuminations, and the like. Luminescent materials used for these EL elements, however, tend to be easily deteriorated by a component such as water, CO2, O2 or the like (hereinafter referred to as a foreign component), which is one of the reasons that prevent the EL elements from having a longer life. Consequently, in order to make the contact with an ambient air less, the elements have hitherto been used in the state of an EL panel in which they are sealed.
As the state in which the element is sealed, a hollow-type sealing in which only an outer periphery of an EL element sandwiched between a substrate and a sealing plate is sealed with a sealing layer (resin layer) including a resin or the like is known, and such hollow-type EL panels are disclosed in Japanese Patent Application Laid-Open No. 2005-91874, and the like. According to this publication, in order to prevent the travel of the foreign component in the resin layer, the EL panel is added with layered (flat) fillers.
Alternatively, as a state of sealing are known a hollow-type sealing in which only an outer periphery of an EL element sandwiched between a substrate and a sealing plate is sealed with a sealing agent (adhesive) including a resin or the like, and a solid sealing in which a whole area of an EL element sandwiched between a substrate and a sealing plate is filled with a curable resin to produce an adhesive layer is known. The hollow-type EL panels and the solid sealing-type EL panel are disclosed in Japanese Patent Application Laid-Open No. 2002-260849, and Japanese Patent Application Laid-Open No. 11-224772, respectively. In the EL panels shown in the publications, projections and depressions are formed on a sealing plate or an extraction electrode part to try to improve adhesion between the sealing plate or extraction electrode part and a substrate. In the resin layer sandwiched between the substrate and the sealing plate at its top and bottom sides, the foreign component travels predominantly in an orthogonal direction in relation to a thickness of the resin layer, namely a surface direction of the substrate. As to the resin layer of the above-mentioned conventional EL panel, when it is coated on the substrate or it is elongated with pressure between the substrate and the sealing plate, the adhesive flows in a surface direction of the substrate, whereby the fillers contained in the resin layer lie in the surface direction of the substrate. In other words, the fillers run in a line parallel to the surface of the substrate, in which direction the foreign component travels predominantly, whereby an effect for inhibiting the travel of the foreign component is very low, and lives of the EL panels cannot be sufficiently extended.